For companies built on buying sprees, the M&A slide deck is the easy part. The hard slog starts when dozens—or hundreds—of small ledgers, price lists, and order-entry screens have to behave like one business. That’s where the unglamorous question of ERP integration sits. Some serial acquirers argue that great capital allocation and a light operating touch are enough; others quietly spend to wire acquired units into a common backbone. The choice shows up later—in how fast synergies appear, how reliably numbers roll up, and how much headroom a group has to keep compounding.

The strongest empirical clue that plumbing matters comes from the information-systems literature, not the IT vendor aisle. A multi-firm study finds that when acquirer and target run on the same ERP vendor, the combined company posts shorter operating cycles and shorter audit delays after the deal—shorthand for cleaner closes and faster cash conversion. Management forecasts also get more accurate, suggesting that better system compatibility improves control of the business, not just the books.

Zoom out and the pattern holds in capital markets. Research on acquirers’ cross-business IT integration capability—how well a parent can make disparate systems talk—links that muscle to higher acquirer value creation in M&A. Markets, in other words, ascribe a premium to buyers that have proven they can integrate the pipes as well as the P&L.

Practitioners see the same thing from another angle. Bain tracked 1,700 companies over a decade and found that frequent, skilled acquirers beat the crowd on total shareholder return. The firm argues a key ingredient is repeatable process and systems integration, noting that weak integrators carry four to five times as many applications and two to three times the IT cost burden, making every subsequent deal more expensive. That is the hidden tax on a “don’t-touch-the-systems” doctrine.

The integration playbook doesn’t have to be doctrinaire. Boston Consulting Group’s PMI work puts technology and data platforms at the center of deal value, estimating that tech directly delivers about a tenth of synergies and enables up to 85% of broader business synergies across cost buckets. That framing supports hybrid approaches many serial acquirers now use: standardize the finance spine and master data to get one version of truth, then migrate operational systems at a pragmatic clip.

Speed matters, but so does sequencing. EY promotes a two-tier “landing-zone” ERP for serial buyers—an interim home that gives day-one visibility into critical KPIs and cash without forcing a rushed, full-stack migration. Done right, that sort of scaffold shortens the time to synergy, limits business disruption, and lowers one-time IT integration spend.

Culture and control complicate the decision. Holding-company purists can point to storied decentralizers that never chased ERP uniformity and did just fine. But that model works best when the parent promises no operating synergies and the portfolio units truly run alone. The moment a group leans on group purchasing, shared logistics, cross-sell, or centralized compliance to justify multiples, visibility becomes non-negotiable. Fragmented ledgers slow working-capital discipline, blur pricing actions, and raise the odds of control issues surfacing at the worst possible time. For programmatic acquirers, the question isn’t “ERP or autonomy,” it’s which minimum viable layer gets centralized early so the rest of the business can stay focused on customers.

There’s a learning curve, too. Case work on serial acquirers shows integration know-how accumulates the same way operating excellence does—deal after deal, with playbooks that decide what gets absorbed, what coexists, and when to renew systems entirely. Consultants can help, but repeat winners tend to build internal muscle that sets the cadence: stabilize, standardize the financial core, harmonize master data, and then refactor the rest with intent. The payoff is capacity—the ability to close the next acquisition without tying knots in the last one.

For investors, the tell is in the run-rate, not the rhetoric. If a serial acquirer promises cost leverage but organic growth and margin trajectories are perennially “postponed” by integration noise, assume the pipes aren’t there yet. If working capital tightens, close cycles shrink, and synergy delivery accelerates within the first few quarters, odds are the backbone is real—even if management never utters the acronym. ERP integration isn’t a religion; it’s infrastructure. In a roll-up, infrastructure decides whether scale compounds or just accumulates.